Release coupling for well casings



(a? March 22, 1949.

E. C. M MANAWAY RELEASE COUPLING FOR WELL CASINGS Filed Jan. 5, 194

2 Sheets-Sheet 1 ZSnneptor Bu fli CM Manaway i C(ttornegs Patented Mar. 22, 1949 RELEASE COUPLING FOR WELL CASINGS Edward C. McManaway, Ashland, Ohio, assignor of one-half to Glenn B. Harmon, Wooster, Ohio Application January 5, 1946, Serial No. 639,350

Claims.

The invention relates to well casings and more particularly to a release coupling for such casings, and the present application is a continuation in part of my abandoned application Serial No. 561,691, filed November 3, 1944.

In the drilling of oil and gas wells, and the like, the lower section or sections of the casing or pipe sets in mud, settlings or cuttings, making it impossible to pull the casing'or pipe without cutting or shooting it loose from the bottom section.

It has heretofore been common practice in seting a casing in a well to make up the last joint loose in the coupling so that after the casing has been allowed to set for the desired time the connection may be backed off.

Frequently the threads in the coupling become galled or crossed, so that considerable difficulty is sometimes experienced in breaking the connection, often resulting in backing the casing off at the wrong joint.

In order to overcome this difilculty what is known as a back-01f tool is sometimes employed, but this requires considerable additional time and labor and is a troublesome operation, and if the threads are burred in coupling where the joint is broken out, it is very difficult to start new threads in it again.

When running a casing it sometimes happens that the bottom packer or shoe does not seal to cut the flow of water, and with the types of release couplings at present in use it is impossible to lift the entire string of casing to seal oil the joint by mudding or cementing the bottom packer or shoe, because the rivets shear off when the casing is originally set on bottom so that it is impossible to pull it without pulling the coupling in two and causing all of the upper part of the casing to be taken from the hole, while the bottom section remains in the hole and requires a fishing Job to pull it from sealing off the joint at the lower end.

Under present practice, when running a casing down, if the bottom of the casing strikes an obstruction the coupling is sometimes accidentally released causing considerable extra work and trouble, requiring that the entire casing be lifted and the bottom section removed by a fishing operation requiring extra time and labor.

It is an object of the present inventin to provide an improved release coupling by means of which the entire device is rigid and solid when running casing down so that if the bottom of the casing should strike an obstruction or tight place the coupling will not be accidentally released.

Another object is to provide a release coupling which is fool proof and which requires a positive action by the drillers to release it.

Still another object of the invention is the provision of a release coupling which will permit the casing to be raised or lowered without releasing the coupling and in which there is no danger of the lower sections dropping down the hole since the release coupling will not accidentally release.

A further object is to provide a release coupling by means of which the lower section or sections of the casing may be quickly and easily released from the remainder of the casing in the event the lower section sets in mud, settlings or cuttings, making it impossible to pull the entire casing or pipe.

A still further object is the provision of a release coupling comprising upper and lower sections having regular tapered right hand pipe threads for connecting sections of well casing or pipe thereto, left hand threads being povided for connecting the two members of the coupling together and a collar being located between the members and connected to the upper member by means of the left hand threads.

Still another object of the invention is the provision of a release coupling of the character referred to in which the upper section of the coupling has internal pipe threads for receiving the usual pipe threads at the lower end of a length of well pipe or casing and the lower section of the coupling is provided with external pipe threads for insertion into the usual threaded collar at the upper end of a length of well pipe or casing.

The above objects together with others which will be apparent from the drawing and following description, or which may be hereinafter referred to, may be attained by constructing the improved release coupling in the manner illustrated in the accompanying drawings in which;

Figure 1 is a vertical, longitudinal section of a portion of well casing or pipe with the improved release coupling applied thereon;

Fig. 2 is an expanded, perspective view of the three parts of the improved released coupling;

Fig. 3 is a vertical, longitudinal section of a portion of well casing or pipe with a slightly modified form of the improved release coupling applied thereto; and

Fig. 4 is an expanded, perspective view of the three parts of the modified form of release coupling shown in Fig. 3.

Referring first to the form of the invention illustrated in Figs. 1 and 2, the improved release 3 coupling consists of three component parts, namefi the upper member II), the collar II and the lower member I2.

The upper member III has the usual inside, tapered, right hand pipe threads I3 within its upper portion, below which is the inside shoulder I4 and the outside shoulder I5. Below the shoulder I5 the member I0 is reduced as at I6 and provided with the outside left hand thread IT.

The lower edge of the collar II fits upon a machined seat I8 in the upper portion of the lower member I2 and upon the inside thereof, the outside of the collar II being machined to fit within the reduced upstanding flange I9 extending upwardly from the seat I8.

The inside of the collar II is provided with the internal left hand threads which engage the external left hand threads I! of the upper member III.

The lower member I2 is provided with the internal left hand threads 2I below the seat l8, for engagement with the left hand threads I! on the lower end portion I B of the upper member ID and may be provided midway of its length with the internal annular rib 22 below which the member I2 is provided with the regular inside tapered right hand pipe thread 23.

As shown quite clearly in Fig. l, the inside left hand threads 20 of the collar II and the threads 2I of the lower member I2 are continuous and matched together so that the collar II and lower member I2 may be simultaneously screwed upon the external left hand threads I! on the lower extension I6 of the upper section III.

The collar II may be held in place within the collar seat of the lower section I2 as by pins 24 which may be located in the collar and lower section I2, preferably through the bottom of the collar and the seat I8 as shown in the drawings, although these pins may be radially located if desired.

An ordinary section of well casing or pipe indicated at 25 and provided with the usual tapered right hand pipe threads 25 may be screwed into the tapered right hand pipe threads I3 of the upper coupling member I0 and a similar ordinary section of casing 25' provided with the usual tapered right hand pipe threads 26 may be screwed into the tapered right hand pipe threads 23 of the lower section I2, in assembling the improved release coupling upon a well casing.

The coupling is assembled above ground with a gasket or packing 2'! between the shoulder I5 of the upper section III and the upper edges of the lower section I2 and collar I I to prevent leaks,

by screwing the collar and lower section I2 tightly onto the upper section III. The coupling is then connected to the upper and lower sections 25 and 25' of casing or pipe and the casing is run in the usual manner to the bottom of the hole.

If it is desired to draw or pull the casing, the casing is turned to the right, tightening all joints except the left hand thread joint in the coupling. The casing is turned until the threads II on the upper section II) are screwed out of engagement with the threads 2| on the lower section I2.

At this point the collar II will still be fixed to the section II] through the threads I! and 20 when an upward pull upon the casing will separate the coupling. In the event the pins 2| are located radially through the collar and lower section I2 this upward pull will shear the pins permitting the coupling to separate.

The collar II being then mounted upon the lower end of the threaded extension I6 of the upper section II) will prevent the threads from dropping together and will protect the threads on thereon may be inserted into the internal pipe.

threads 23 of the lower section I2 of the release coupling.

For the purpose of providing means for attaching the lower section of the release coupling to the internal pipe threads upon this usual collar on the upper end of the well pipe or casing, the modified form of the invention, illustrated in Figs. 3 and 4, is provided.

Referring now to this form of the invention, the modified form of the improved release coupling consists of the three component parts, namely the upper member Ifla, the collar Ma and the lower member I2a. The upper member Illa has the usual internal, tapered, right hand pipe threads I3a in its upper portion, below which is located the inside shoulder Ida and the outside shoulder I5a. Below the shoulder lie the member Ina is reduced as at lie and provided with the external, left hand threads IIa.

A machined seat I8a is formed in the upper portion of the lower member I21: and the lower edge of the collar IIa fits upon this seat, the exterior of the collar being machined to fit within the reduced, upright flange I9a which extends upwardly from the seat IBa. Intumed, left hand threads 20a are formed upon the inside of the collar Ila and engage the external, left hand threads IIa of the upper member Illa.

Internal, left hand threads 2Ia are provided on the exterior of the lower member I2a, below the seat I8a, for engagement with the external,

left hand threads IIa on the lower end portion I6a of the upper member I (la, and said lower member may be provided midway of its length with the internal, annular shoulder 22a and the external annular shoulder 22b, below which the member I2a is externally reduced and tapered and provided with external, tapered, right hand pipe threads 23a.

Referring to Fig. 3, it is clearly seen that the internal, left hand threads 20a, of the collar Ila, and the internal, left hand threads 2Ia, of the lower member I2a, are continuous and matched together so that the collar Na and lower member I2a may be simultaneously screwed upon the external, left hand threads I'Ia or the lower extension IBa of the upper section Illa.

For the purpose of holding the collar Ila in place within the collar seat of the lower section I2a, pins 24a may be located in the collar and the lower section I2a, preferably through the bottom of the collar and the seat I 8a, as shown in Fig. 3, although if desired, these pins may be radially located through the collar and the lower member of the coupling.

A section of well casing or pipe, the lower end portion of which is indicated at 25a, is provided with the usual external, tapered, right hand pipe threads 26a which may be screwed into the tapered, internal right hand pipe threads I3a of the upper coupling member IIJa, as shown in Fig. 3.

An ordinary section of well casing or pipe, the upper-$nd portion of which is indicated at 252; in Fig. 3, and having the usual external, tapered, right hand pipe threads 2612, is provided with the threaded collar 28 usually mounted upon the upper end of each section of well casing or pipe.

This collar 28 is provided at its upper end with the usual internal, right hand, tapered pipe threads 29 which in ordinary practice receive the external pipe threads at the lower end of the next upper section of pipe or casing. These internal pipe threads 29 of the collar 28 may be screwed upon the tapered, external pipe threads 23a. of the lower member [2a of the coupling in assembling the improved release coupling upon a well casing or pipe.

The coupling is assembled above ground, in the manner above described with reference to the form of the invention illustrated in Figs. 1 and 2, and a gasket or packing 21a may be located between the shoulder a of the upper member and the upper end of the lower member of the coupling to prevent leaks at this joint, and the coupling is connected to the pipe sections 25a and 25b, as above described, and the casing is run in the usual manner to the bottom of the hole.

If it becomes necessary to pull the casing, it is turned to the right, tightening all joints except the left hand thread joint in the coupling and the turning movement of the casing is continued until the threads l'la on the upper member IOa are screwed out of engagement with the threads Na in the lower section l2a.

At this point the collar Ha will still remain fixed to the upper member Illa through the left I hand threads Ila and a so that an upward pull upon the casing will separate the coupling members from each other. In cases where the pins 24a are located radially through the collar and lower member |2a this upward pull upon the casing will shear the pins permitting the coupling members to separate.

The collar I la is then mounted upon the lower portion of the externally threaded extension IBa of the upper member Illa and will prevent the threads from dropping together and protect the threads on the upper member Illa while the easing is being pulled. Thus the casing is entirely free from the lower section or sections 25b of well casing or pipe, which is set in mud or settlings at the bottom of the hole, and all except this lower well casing or pipe section can be easily pulled.

From the above description of the form of the invention disclosed in Figs. 3 and 4 it will be obvious that it is not necessary to remove the usual threaded collar 28 from the upper end of the lower casing or pipe section 25b, but instead the internal, pipe threads 29 of this collar are screwed upon the tapered, threaded extension 23a of the lower coupling member.

It will be seen from the above that the entire device is rigid and fastened solidly when running casing down so that if the bottom of the casing should strike an obstruction or tight place in the hole the coupling will not be accidentally released. The coupling is absolutely fool proof as it requires a positive action by the drillers to release it.

In running the casing it is possible to raise or lower the casing without releasing the coupling permitting it to be driven past tight places without danger of releasing the coupling and allowing the lower section or sections to be dropped down into the hole.

Besides being entirely fool proof it will be seen that when the casing is all in and the bottom section is set in the bottom of the hole, if for some reason it is desirable or necessary to pull all of the casing, for example where the water is not completely sealed oil, the coupling may be released as above described and the casing pulled after which the bottom section or sections may be retrieved by means of fishing tools after which the whole apparatus can be reassembled and rerun.

It will also be evident that in running casing with the improved coupling, in the event the bottom packer or shoe does not seal to cut the flow of Water, the entire string of casing may be released and by means of cementing or mudding the bottom packer or shoe the joint may be sealed off and the casing again lowered.

I claim:

1. A release coupling for well casing comprising an upper member hatingintemaLrgght -hand pipe thws in its upper portion for connection to a sectionof well casing and having external left-hand threads around its lower portion, a l'evm'fieinmfia'vrng internal left-hand threads in its upper portion and an annular seat above said internal left-hand threads, and a collar located in said annular seat and having internal left-hand threads, the internal left-hand threads of the lower member and collar engaging the external left-hand threads on the upper member and right-hand pipe threads at the lower portion of the lower member for connection to a section of well casing.

2. A release coupling for well casing comprising an upper member having internal right-hand pipe threads in its upper portion for connection to a section of well casing and having external left-hand threads around its lower portion, a lower member having internal left-hand threads in its upper portion and an annular seat above said internal left-hand threads, and a collar located in said annular seat and having internal left-hand threads, the internal left-hand threads of the lower member and collar engaging the external left-hand threads on the upper member, pins engaging the collar and the lower member, andmhand pipe threads at the lower portion of the lower memberior ccTrlnc'tion to a section of well casing.

3. A release coupling for well casing comprising an upper member having internal right-hand pipe threads in its upper portion for connection to a section of well casing and having external left-hand threads around its lower portion, a lower member having internal left-hand threads in its upper portion and an annular seat above said internal left-hand threads, and a collar located in said annular seat and having internal left-hand threads, the internal left-hand threads of the lower member and collar engaging the external left-hand threads on the upper member and internal, right-hand pipe threads at the lower portion of the lower member for connection to a section of well casing, there being an external, annular shoulder on the upper member at the upper end of the left-hand threads thereon, the upper ends of the collar and of the lower member abutting said shoulder.

4. A release coupling for well casing comprising an upper member having internal right-hand pipe threads in its upper portion for connection to a section of well casing and having external lefthand threads around its lower portion, a lower upper portion and an annular seat above said internal left-hand threads, and a collar located in saicgannular seat and having internal lefthand threads, the internal left-hand threads of the lower member and collar engaging the external left-hand threads on the upper member, pins engaging the collar and the lower member, and right-hand pipe threads at the lower portion of the lower member for connection to a section of well casing, there being an external, annular shoulder on the upper member at the upper end of the left-hand threads thereon, the upper ends of the collar and of the lower member abutting said shoulder.

5. A release coupling for well casing comprising an upper member having internal right-hand pipe threads in its upper portion for connection to a section of well casing and having external left-hand threads around its lower portion, a lower member having internal left-hand threads in its upper portion and an annular seat above said internal left-hand threads, and a collar located in said annular seat and having internal left-hand threads, the internal left-hand threads of the lower member and collar engaging the external left-hand threads on the upper member and right-hand pipe threads at the lower portion of the lower member for connection to a section of well casing, there being an external, annular shoulder on the upper member at the upper end of the left-hand threads thereon, the upper ends of the collar and of the lower member abutting said shoulder, there being a gasket between said shoulder and the upper ends of the collar and of the lower member.

EDWARD C. MCMANAWAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 47,613 Bolles May 9, 1865 2,070,077 Davis Feb. 9, 1937 2,218,496 Phillip Oct. 15, 1940 

